so glad this thread made it back from 2010 i'm interested to see what you guys put together.

 

The tables control the amount of additional ISCV demand (ISCV step increase) when the PS pump is doing work, i.e., when turning the steering wheel or when holding the steering wheel during a turn.

 

Anyone ever identify these tables for an evo 8 rom??

 

I caught wind of this thread while troubleshooting my issues as well. By evo 8 rom, I guess you asking about the 9417 v7 rom? I have that one, and the ISCV stuff in the ISCV control category that sort of matches up with all of the things here like CTS adder and Baro adder and all that....some don't seem right.

Specifically these all seem a little off, judging by what "meat" is in the tables, since it's so erratic.

Baro Adder sub 1a61c
maybe both post wot tables
Baro Adder sub 1f6e6
IATS Adder
RPM Adder rpm>4500, load >170, speed > 12

 

Has a solution been found for cars that are stalling when coming to a stop with ac on? Aside from the obvious fixes like properly setting biss screw and increasing steps in the desires iscv with ac on section.

I've got mine idling flawless everywhere but when coming to a stop with ac on. Adding 40-50 additional steps makes zero difference.

 

I have always theorized that the ISCV system had learned trims. I came up with this theory because I noticed ISCV changes made more affect after resetting the ECU, which lead me to believe there was trims.

Being able to log those trims help in a big way, in making sure everyone will have solid idles.

Anyone wanna setup some Evoscan .xml's for those data items?

 

Are you sure you were adding 40-50 steps and logging it to verify? It's hard to believe that 40-50 steps would have 0 effect.

I'm pretty sure there are ISCV trims and IIRC there was something mentioned about them recently...maybe by mrfred? I thought I saw some mention about them somewhere.

Edit: Look back one page at post #116 by mrfred.

 

You can add all the ISCV steps in the world. The car will just idle higher, but if you clutch in while moving the RPMs will drop down to 400-500 and stumble around a while before the RPMs shoot up.

My car idles fine. The injectors are scaled properly. I've tried: changing ISCV valves, BOV's, injectors, front O2 sensors, MAF's (even upside down and backing out calibration screws), cleaning throttle body, replacing TB shaft seals, adjusting ISCV steps, MAF comp tables, BISS adjustements (SAS and non SAS). Changing idle timing, sometimes dramatically, resetting ECU after flashing. Boost leak tested a dozen times.

No matter what I do, the car will fall right past idle RPM (it tries to slow down) and bog for a while before idling up. It's infuriating. I'm convinced it's not mechanically related, and has to do with the ROM. L2r99gst got it right in requesting a MAF clamp (load increases when it stumbles) to help prevent it.

I'm grateful to all the gents who have made the stock ECU so formidable in the tuning realm, but believe there is still a lot to be learned from the idle subroutines. I almost wish mrfred, tephra, acamus and others had the stumble issue with 9417/9653 as that certainly would have added more incentive to figure it out.

 

I quoted that post in the post you quoted. LOL.

 

When Monsieur Fred says he needs to define the range, that's the min and max we'd set in evoscan so that the data makes sense right? I'm certainly interested in seeing that when it gets done, because I change stuff with my ISCV trying to address issues like most others see, but the dang thing just seems to self compensate....it's like trying to scale fuel injectors by using the WB, instead of the trims (aka peeing into the wind, lol).

So, subscribing to this one, in hopes of more understanding on my part about idle, and maybe even if there is a table that affects the transition idle, between clutch in and clutch out or something like that.

 

Does the 'Idle Stepper Lookup Table' get added to the 'Desired ISCV Initial Step Position' values or does it only come into play during decel or something? Do people actually see a stepper value of "7" at idle? (assuming the car was basically stock lol) I guess I am unclear when the idle stepper table values are kicked in.

Also, for the Desired ISCV Initial Step Position with AC-off DRIVE, could that possibly be when the speed sensor is not stationary? Or is it just 100% mislabeled?

-Jamie

 

It seems to have an effect on my car with A/C on or off, coasting or not....so I think it is 100% mislabeled. I can't very well put my finger on what the thing does, but...it does "something".

 

I believe it was said that the Drive-Neutral references were an artifact of the original ecuflash definitions, and that further dis-assembly revealed no differentiation in the code between stationary-drive parameters in the ISCV code.

Seems to be an awful lot of interest in this subforum on idle control recently...maybe we're close to another break through.

 

replace the IAC motor itself yet?

 

Yes, I referred to it as ISCV. And I changed it. And it still stumbles.

The car idles fine. The car drives fine. It makes great power. It just won't stop at idle as RPM's drop, whether it be clutch in while driving, or free revving in the driveway.

It's incredibly frustrating, even more so since some people are able to cure the issue with ISCV, BISS and timing tweaks and others aren't. I was able to get the car to catch idle and not stumble using a ported stock exhaust manifold, TME turbo and stock UICP. With a HKS 7460, JMFab Exhaust Manifold, and CBRD UICP I cannot for the life of me get it to catch idle.

With ISCV being "the final frontier" in the stock ECU disassembly, I'm hopeful that the smart guru's and contributors in this forum can come up with a solution to the issue that does not involve SD (which brings it's own idiosyncrasies). This thread is a step in the right direction.